Cuticular hydrocarbons are among the prime candidates for nestmate recognition in social insects. We analyzed the variation of cuticular hydrocarbons in the termite species M. subhyalinus in West Africa (Comoë National Park) on a small spatial scale (< 1 km). We found considerable variation in the composition of cuticular hydrocarbons among colonies, with four distinct chemical phenotypes. Different phenotypes occurred within each of the four habitats. The difference between these phenotypes is primarily due to unsaturated compounds. A clear correlation between the difference of the hydrocarbon composition and the aggression between colonies was found. This correlation also holds in a multivariate analysis of genetic similarity (measured by AFLPs), morphometric distances (measured by Mahalanobis-distances). as well as geographic distances between colonies. In a more detailed analysis of the correlation between the composition of cuticular hydrocarbons and aggression, we found that no single compound is sufficient to explain variation in aggression between pairings of colonies. Thus, termites seem to use a bouquet of compounds. Multiple regression analysis suggested that many of these compounds are unsaturated hydrocarbons and, thus, may play a key role in colony recognition.

Intraspecific colony recognition in the termites Macrotermes subhyalinus and M. bellicosus was investigated over two field seasons in Comoë-Nationalpark (Ivory Coast). Behavioural tests with major workers and minor soldiers, respectively, were performed using neutral arenas of covered plastic dishes. For each species, termites were sampled by baiting from 10 field colonies randomly chosen at four different sites. Major workers and minor soldiers of both species were capable of differentially discriminating between members of various colonies. In major workers of M. subhyalinus this discriminatory ability was expressed as varying degrees of aggression, whereas major workers of M. bellicosus showed different degrees of examination behaviour. Minor soldiers of both species reacted to foreign colony members with different levels of aggression. Thus, M. bellicosus displayed a more subtle form of discriminatory behaviour. Mound volume was measured as a parameter for colony size and stage of colony development. Aggression (in major workers of M. subhyalinus) and examination behaviour (in major workers of M. bellicosus) were not correlated with differences in mound volume and thus differences in size or age of the involved colonies. Aggression and examination behaviour respectively of major workers were not correlated either with the spatial distance between the colonies. We found cases, where individuals from neighbouring colonies showed either no aggression/examination behaviour or a high level of aggression/examination behaviour. Thus, there was no indication of a dear-enemy phenomenon. The behaviour of colony discrimination was found to be consistent over the two years for both species.

The system of underground passages and storage pits used in foraging have been excavated in two nests of the termite Macrotermes subhyalinus in West Africa (Ivory Coast). A detailed qualitative description of the morphology and the dimensions of the passage network is given. Three types of passages could be distinguished: radial passages, big cross passages and small cross passages. These varied in their dimensions and their functional significance. Density values for the different types of passages and the storage pits in various zones of the two mounds were calculated. Density of total passages varied between 1.46 m/m 2 and 1.80 m/m 2 being in the order of other Macrotermes species with a comparable foraging behaviour.In the second part of the study intraspecific behavioural tests between pairs of colonies of M. subhyalinus and M. bellicosus were performed in neutral arenas and the zones of contact between the corresponding colonies were then excavated. Hints of agonism such as cemeteries with dry head capsules of termites, passage blockings and phenomena of horizontal or vertical passage segregation were found. Generally colonies displaying strong reaction in behavioural tests reacted in the natural context upon contact with deadly conflicts. On the other hand, colonies with a weak behavioural reaction withdrew and blocked the passages without deadly conflicts. For the first time results of laboratory bioassays were connected to unmanipulated field evidence of termite agonism.